Typically, users, which may be people or other systems, engage information technology systems (e.g., commonly computers) to facilitate information processing. In turn, computers employ processors to process information and such processors are often referred to as central processing units (CPUs). A common form of processor is referred to as a microprocessor. A computer operating system, which is software that is executed on a computer, enables and facilitates users to access and operate computer information technology and resources. Common resources employed in information technology systems include input and output mechanisms through which data may pass, memory storage into which data may be saved, and processors by which information may be processed. Often information technology systems are used to collect data for later retrieval, analysis, and manipulation, which often is facilitated through database software. Information technology systems provide interfaces that allow users to access and operate various system components.
Early single chip microprocessors included the Intel 8080 (an 8-bit processor introduced in 1974), the Motorola 6502 (an 8-bit processor introduced in 1977), the Intel 8088 (introduced in 1979 and incorporated into the IBM Personal Computer (PC)). The vast majority of the PC market moved from the Intel 8088 to the 80286 to the 80386 to the 80486 to the Pentium to the Pentium II to the Pentium III to the Pentium 4. While the current microprocessor market is dominated by the Intel architecture, other processors such as the Motorola 68000 and PowerPC have minor market shares.
The various processors employ disparate architectures including a complex instruction set computer (CISC) and a reduced instruction set computer (RISC). Microprocessors provide instruction sets that allow program developers to exploit and use the microprocessors to execute and process information. Typically, program developers use program languages that are compiled into a microprocessor's instruction set by a special program called a compiler. Compilers themselves are made by program developers who use tools to design compilers to produce instructions for a specific microprocessor.
These designs of the microprocessor originated several years ago, and have evolved over time. As the designs have evolved, the clock rate of the microprocessor has been increased to deal with more instructions within a fixed time frame.